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A friend of mine insists that it is pointless to have brake rotors turned since minor imperfections will be worn even. He says If the whole rotor is warped then it should be replaced. I've never had brake rotors turned, myself, but I'm not that hard on my brakes. Whats the story on "to turn" or "not to turn"?
The shop I take my car to does not recommend turning the discs. About the only issue I can see is that when you put new pads on, they are not fully bedded and it may take more brake pressure until they bed, which happens fairly quickly.
Mike
I am from the opposite camp. I live in a mountainous area. I want full brakes now. Not a few weeks or days from now. I lose 800' in elevation just from where I live to the downtown historic area of town.
I turn the rotors when I replace the pads. I want a flat surface to a flat surface.
I have heard but not verified there are some rotors they don't recommend turning however.
Turning brake rotors used to be common when there were such things as "Service Stations". Every service station had the machine and it was easy to drop them off, stop back by in a few hours and pick them up. So it was easy and it was cheap and it worked well. Fast forward to today and just trying to find a place that can turn them that you can trust is a challenge. It's something the people in the business don't even do much, so it's normally a hassle to have them do it. Last set I tried to have turned, I was told "Come get them tomorrow afternoon". I explained that I had the car apart and needed them back today. Didn't matter. Seemed they had one guy that did it and he was busy working on other jobs. I went and bought new rotors for about $25 each at the time, and never tried to have another one turned.
I sure miss Service Stations where they did work like that, patched tires, did the pain in the tail things that you can't find people to do these days.
Given the relative low price of rotors today, replace them. Properly installed pads and new rotors will virtually eliminate any brake squeal. One of the big three, I think it was GM, once tried cutting a V groove in the rotor and produce a brake pad with a corresponding profile to fit the groove. The idea was this would reduce squeal. Don't see any of those on the market these days. The only way to prevent squeal is to use quality components and install them correctly.
Hang and bang shops usually just install new rotors because its quicker. Plus, they don't have to maintain one or more brake lathes. Look at a shop with several bays or more and imagine the down time with mechanics standing in line waiting to turn a set of rotors. Some applications required the rotor to be on the vehicle in order to turn them accurately, which is yet another machine.
The cost of rotors has dropped so much in recent years that it makes sense for the professional installer to have new rotors in stock or out for delivery by the time the car is going up on the rack.
BTW, I don't think of brakes as a stopping device or system, although this is the end result. I think of brakes as an energy converter. They convert the inertia or momentum of the vehicle into heat. It takes a lot of energy to move a one to two ton vehicle forward. That energy doesn't disappear when we apply the brakes, it has to go somewhere. It gets converted to heat.
Hybrid vehicles convert as much off this invested energy as possible into a flywheel rather than just convert it to heat.
No one has yet addressed the question of whether it's necessary to have the rotors turned. The only reasons I can see are if the rotor is not running true, and to get better initial bedding when replacing the pads. I questioned my shop, which is not a "hang and bang" shop, and their answer was that if the rotor is within spec for running true, they do not recommend turning the rotors.
By turning the rotors when they don't need to be turned, all you're doing is taking metal off that doesn't need to be taken off and shortening the life of the rotor. There's a spec for the thickness of the rotor and when they are thinner than that, you need to replace them. So if a shop wished to "pad the bill" they'd turn the rotors ever time they changed the pads. They'd get the cost of the turning and you'd have to replace the rotors faster than if they didn't turn them.
So if you have your rotors turned every time you have the pads changed, for what reason do you do that?
Mike
Turning the rotors when installing new pads, along with making sure the calipers are working properly and greasing the parts that require lubrication, is the surest way to prevent squealing brakes.
I don't know if you can turn the warp out of a set of rotors. The warping occurred as a result of improper lug torque and heat. I would not be surprised if the combination permanently altered the properties of the metal so that it is prone to warping again.
The brake pad warranties we deal with are almost always the result of improper installation.
A rotor can be turned if it is within spec, so long as it does not end up to close to minimal tolerances after turning. You certainly would not want to put a rotor back on that was at or near minimum tolerances.
My understanding is that if the rotor is thick enough that they should be turned so you have good braking surface. If you look closely at a used rotor there will be a series of humps and dips that also match the contours worn into the pads. Changing just the pads results in less than 40-50% contact between each pad and the rotor. This can dramatically affect your stopping distance. Pads don't wear down to match very quickly.
For safety reasons either get new rotors or have the old ones turned whenever you install new pads. The cost of either process will be less than the deductable on your insurance if you hit someone because of reduced braking capacity.
I live in a mountainous area. One of the warrantee issues I had on a new 83 K-5 Blazer was brakes not working properly. We fought brake issues for the entire warrantee period. One time the dealer would replace the pads...the next time he'd turn the rotors and reinstall the same pads. Once the warrantee period was over, I assumed the maintenance on the vehicle. I would remove the rotors and have them turned whenever I replaced the pads. We never had brake problems after I took over the maintenance.
It's a matter of safety. Flat surfaces against flat surfaces..immediately. If you put flat pads against a grooved surface EVENTUALLY the pad may wear to the contour of the rotor but until does you don't have 100% of the available pad surface providing braking force. In mountainous areas it's best to be a little conservative.
The answer to the OP's question is "it depends".
IF, your rotors run true (checked with a dial indicator), IF they do not have grooves cut into them from pad wear, IF the vehicle did not have a problem with surging when braking, and IF the rotors are thicker than the minimum spec, you do not need to turn them.
If your vehicle exhibits brake surge and a dial indicator shows that the rotors are true, then they should be turned or replaced. The reason why is because some rotors can develop hardened spots on them which can cause the same sympton as a warped rotor. This typically happens on heavier vehicles that are subjected to higher brake loading and temperatures.
They should be turned or replaced also if they have a few thousands of runout or are grooved, presuming that they will still meet minimum thickness specs after turning.
Warped rotors can result from improper torque (or inproper torque sequence) when attaching wheels too.
My local NAPA dealer turns them in an hour for like $10 each, so why not? I like to get the ridges off and especially the rusty ridge at the outside that is always bigger than the worn section of the rotor. Plus, how thin will you let your rotors get if you don't get them measured once in a while? I suppose that if I didn't have a shop close and the rotors still looked in good shape, I would consider leaving them on for one more set of pads.
Ok, those that don't turn, just reuse, how many sets of pads have you gotten out of one rotor?
Ken,
Have you ever tried cross drilled rotors on your rigs?
Greg.....I considered it on a used F-350 4-WD I bought. I had to do some serious front end work (shim the straight axle FE), realign FE and replace both rotors, calipers and steering wheel pump. But I have considered it.
You may want to consider them in the future. They are an effective solutions to poor brake performance and/or life on the bigger rigs like yours.
Whenever I do my brakes, I have the rotors (or drums) turned, or, if they are too thin, replaced.
I'd still love to know what the combination of parts was on our (now gone) '96 Dodge Grand Caravan. My parents were the first owners, never did the brakes, and I first did the front brakes on it at 105,000 miles. After that, I would get about 25-30,000 miles between rehabs.
The pads they put on at the factory are generally not the same pads you get at the dealer. I had several Tacoma pads I had to source from the dealer for a short while many years ago. The OEM pads lasted 35k-40k miles. The OES pads I bought from the dealer were no better in terms of performance or life than subsequent after market pads.
OEM parts are designed to exceed the warranty period. Anything after that is icing on the cake.
When replacing pads, rotors should ALWAYS be turned, why put a worn surface against a new surface. Would you edge glue a freshly jointed piece of oak against a rough sawn piece of oak? Same difference in my book. Measure the rotors and if they are close to the disgaurd tolerance, then replace them. We turn rotors on about 60% of brake jobs we do.
I'm going to take the fifth on that. BTW, what is the statute of limitations on such an act, if one were to be committed. Just asking for a friend. :DQuote:
Originally Posted by Jeff Monson
I'll have to let the SMC jury decide that one Greg, I'd say something along the lines of a loss of a finger, toe or some type of digit.Quote:
Originally Posted by Greg Peterson
Nope. I run them through 2 sets of pads and then toss them. Not worth the risk and they aren't expensive. The Brembos or Centrics are both only about 50 bucks each. Get about 30-50k miles out of them. They probably could be turned but its not worth the risk.
" Back in the day", when I used to do brake jobs and front end work to supplement the income, we used to turn rotors/drum. However, they were turned to remove the liability of brake failure more than anything else.
The state required that the brake to rotor contact area had to be 100%. The only way to guarantee that there was 100% pad to rotor contact was to turn the rotor/drums.
Each vehicle is different, and with the cost of a replacement set of rotors, and the ease of installation, it makes more sense to replace them with the pads and bed them in together.
I don't turn rotors, I just replace them. But then, I do my own brakes.
In Ken's case, I don't see a set of "typical" cross drilled rotors. It is true that the cross drilling disapates heat, but there are many instances of premature cracking of rotors at the holes in extreme heat situation. A 3/4 ton truck pulling a trailer, on mountain passes, needs brakes.
Occasionally I’ll catch a segment of Goss’ Garage on PBS Motor Week.
Goss cautioned on one show about brakes that most aftermarket rotors are basically inferior to OEM rotors and that you’re better off turning and reusing a OEM rotor rather relying on a knock-off made in China or some third-world country where the emphasis is on “Cheap” rather than quality.
New doesn’t necessarily mean it’s better or even safe.
He also said that quality replacement rotors are still available but I don’t remember him offering any suggestions on where to find them.
Gluing wood and using brakes are not similar.Quote:
Originally Posted by Jeff Monson
with the cost of rotors so cheap it does not make sense to turn them...i replaced front brake pads several time and never had a problem with rotors...but in the case of a warped rotor it should be scrapped as it is inferior.
Rotor prices vary dramatically depending on what vehicle you drive and what rotors you put on that vehicle. Check out the prices for a rotor for a 1 ton Ford F-350 pickup and tell me they are cheap.
There is nothing wrong with turning a rotor if it is thicker than the "discard" thickness established by the manufacturer. In the case of my F-350 rotors were $100 each over 15 years ago....and those rotors were not from the OEM but rather a local Napa dealer. At the time I could have both rotor turned for $20.
2ndly......don't take it for granted that new rotors are perfect. The set I put on that F-350 wasn't and I had to turn the new rotors.
There is OEM, OES and aftermarket. It is not uncommon for the OEM part to only be available at the factory where the assembly is done. Those parts are not usually made available to dealerships or aftermarket channels. OES (original equipment supplier) is usually what dealerships and aftermarket distributors carry, although there are some exceptions. Then there is aftermarket supplier, often times an OES. Aftermarket parts can be low quality or higher quality than the OEM. A quality aftermarket manufacturer has the distinct advantage of designing around any flaws in the field tested OEM part.Quote:
Originally Posted by Harry Hagan
Yes, there are cheap knock offs out there. Most of us can remember a time when Made In Japan meant poor quality. China is getting their processes together. The quality depends in large part in diligent they are in overseeing QA at the factory. I think Grizzly is a good example of this arrangement.
All things being equal, I would prefer manufacturing in USA, but in fairness, any poor quality coming out of China is a reflection of the companies desire to produce a good product rather than ability.
I am another one who used to supplement his income by doing brake jobs. The standard 25 years ago was to turn them. The new rotors were $70+ and turning was only $10. No brainer back then. Today the rotors are $25-35 and turing in my area is $15-20. For the $10-15 per corner savings I just replace now. It saves time. I can walk out of the auto parts store with everthing I need to get the job done instead of dropping off the rotors and coming back 1-2 hours later to pick them up.
Maybe I'm just lucky but I've never seen a bad rotor out of the box. Not saying it never ever happens but I've read and talked to people who have claimed this and then you find out that they didn't take a wire brush to their hubs or bother to clean and lube everything so the rotor never sat right in the first place...Quote:
Originally Posted by Ken Fitzgerald
I just replaced all my brakes a few months ago and it took me over 5 hours to do the rotors, pads, replace all the fluid, and go over the calipers. Smooooooooooth very firm gripping. :) I just took the Centric rotors out of the box and cleaned all the shipping oil off of them, no turning.
Speaking as an ASE Certified, former professional mechanic with extensive experience is braking and suspension systems, I can say with some authority, that it depends on a LOT of factors, not the least of which, the thickness of the rotors themselves, and the OEM specs on those same rotors.
New rotors should be turned with a light pass to remove any surface imperfections caused by the manufacturing, and any warpage caused by shipping and storage.
OEM rotors typically use seriously old technology. For my own personal vehicle, due to other modifications I made. I felt I needed more stopping power, with better heat dissipation than OEM could provide, so when the OEM rotors warped (35" tall rubber will do that...) I replaced them with Cryoslot cryogenically treated slotted rotors, and fitted them with EBC Greenstuff 6000 pads. Hauls my heavy truck, and the heavy loads I haul down to a stop quick...
I drop 700' in elevation to get to the rest of the city here. One of the streets has an 11% grade.
We climb 2000' in elevation to get out of town in any direction. The song "Hot Rod Lincoln" written by Charlie Ryan as attributed at his website was about the old Lewiston Grade. He performed in a local bar and wrote the song after racing a friend to the top of the canyon rim. The current Lewiston grade drops 2000' with only 1 major turn and 5 "runaway truck ramps" in it's 6 mile descent. THe upper part of the descent is 6% grade and the last half is a 7% grade. At the bottom there is a 45 mph "Y". There have been 9 truckers killed at the bottom of that hill since we moved here 29 years ago. They failed to gear down and burned their brakes up before they got to the bottom. Then rolled their trucks at the bottom.
We have to take brakes seriously.
I change brake fluid every 2-3 years too.